1. Field of the Invention
The present invention relates to a battery device used as a portable power source, an electronic apparatus in which the battery device is detachably mounted and used, and a battery system including a combination of the electronic apparatus with the battery device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2000-243365 discloses an example of a battery device of the related art as a portable power source. Japanese Unexamined Patent Application Publication No. 2000-243365 discloses a battery pack in which a rechargeable battery cell used as a power source for an electronic apparatus is stored; a battery mounting device on which the battery pack is mounted; and an electronic apparatus including a battery mounting mechanism on which the battery pack is mounted. The battery pack disclosed in Japanese Unexamined Patent Application Publication No. 2000-243365 includes “a battery cell; a case in which the battery cell is stored; an output terminal which is provided in the case and outputs power of the battery cell; and a second surface of the case which is provided continuously with a first surface of the case having the output terminal and provided approximately perpendicular to the first surface, where a recess is formed with a plurality of steps in an approximate center of the second surface”.
It may be expected that the battery pack having such a configuration may be prevented from being inappropriately mounted on a battery mounting device which is supposed to be incompatible (paragraph [0161] of the specification), for example.
Japanese Unexamined Utility Model Application Publication No. 2005-190929 discloses another example of a battery device of the related art. Japanese Unexamined Utility Model Application Publication No. 2005-190929 discloses a battery device and an electronic apparatus operated using the battery device. The battery device disclosed in Japanese Unexamined Utility Model Application Publication No. 2005-190929 includes “a case having a width, a thickness, and a length; a rechargeable battery provided in the case; and a battery side terminal provided on a surface of the case and connected to the rechargeable battery, where the battery device is inserted in the length direction into a battery housing chamber of an electronic apparatus and the battery side terminal is connected to a housing chamber side terminal of the battery housing chamber. A guide groove is formed in each side of the case in the crosswise direction, where the guide groove extends in the length direction and is engaged with a protrusion provided in the battery housing chamber to position the case in the thickness direction in the battery housing chamber”.
According to the battery device having such a configuration, it may be expected that “since a guide groove is formed in each side of the case in the crosswise direction of the battery device, where the guide groove extends in the length direction and is engaged with a protrusion provided in the battery housing chamber to position the case in the thickness direction in the battery housing chamber, it is possible to store, in the battery housing chamber, multiple types of battery devices different in thickness of the case, that is, different in volume” (paragraph [0005] of the specification).
However, in the battery device disclosed in Japanese Unexamined Patent Application Publication No. 2000-243365, a recess formed with a plurality of steps is provided in an approximate center of a rear surface of the case in which the battery cell is stored, and a protrusion corresponding to a shape of the recess is provided in a mounting portion of the electronic apparatus in which the battery device is mounted, in order to discriminate a type of the battery device. As a result, when a new battery device is developed, it may be necessary to increase the number of the steps in the recess of the battery device and provide a protrusion corresponding to the recess in the mounting portion of the electronic apparatus, and thus the recess of the battery device and the protrusion of the mounting portion have complicated shapes.
Further, each of the battery devices disclosed in Japanese Unexamined Patent Application Publication No. 2000-243365 and Japanese Unexamined Patent Application Publication No. 2005-190929 is formed as an exclusive component that may be mounted only on a mounting portion having a specific configuration of an electronic apparatus. Accordingly, one battery device may be mounted on an electronic apparatus having a mounting portion corresponding to the battery device, and a battery device corresponding to the electronic apparatus may separately be prepared for another type of an electronic apparatus including a mounting portion having a different mounting structure.